WordPress post image to show not the featured image - php

Question

I have a site in WordPress, and I want to display the WordPress post first image which is displayed in the post but remember not the featured images. so how to show it in the post and i want my post like below
this is how blog design should be
This is the code
<div class="col-md-3 small-post-img">
<a href="<?php the_permalink() ?>">
<?php the_post_thumbnail(); ?>
</a>
</div>
It not taking the the_post_thumbnail code because there is no any featured image in the post, but I have added the images in the inside post content. I want that post images as featured image.

Answer 1

Put this in your theme's functions.php file
function ash_post_first_img($post_content){
preg_match_all('/<img[^>]+>/i', $post_content, $content_all_images);
preg_match_all('/src="([^"]+)"/i', $content_all_images[0][0], $content_image);
if (isset($content_image[1][0])) {
return $content_image[1][0];
} else{
return 'http://example.com/defaultimage.jpg';
}
}
and use this function ash_post_first_img(get_the_content('')); where you want to display image's url "single.php or post.php"
<div class="col-md-3 small-post-img">
<a href="<?php the_permalink() ?>">
<img src="<?php echo ash_post_first_img(get_the_content('')); ?>">
</a>
</div>
Change "http://example.com/defaultimage.jpg" to the default image url if no image is found.